An image capture device can capture audiovisual content from various perspectives, which may be useful for various objectives. As one example application, an image capture device can be used to perform life logging, in which images, image streams, and in some implementations, associated audio, are captured by the image capture device over a period of time to document various events that occur during the user's daily life. Life logging can be performed to assist in memory retention in the elderly, to share the user's perspective or experience with other persons, or to simply document the various events that the user experiences so that the user can revisit such events in the future and enjoy their recollection. For example, a parent may enjoy reviewing images of their child blowing out candles on a birthday cake.
Thus, an image capture device can be used to capture particular events in a person's life in much the same manner as the person would use a traditional camera to record such events. However, an image capture device may provide the further benefit that the user does not have to actively operate a camera during the event to capture the event. Instead, the user is able to fully engage in and enjoy the event while the image capture device captures imagery, and in some cases, audio of the event. For example, the parent can enjoy and participate in their child blowing out candles on the birthday cake without the distraction of operating a camera, while still obtaining imagery of the scene to enjoy at a later time.
Furthermore, an image capture device may be relatively more adept at capturing and curating audiovisual content, such as imagery of candid moments, versus a traditional camera. In particular, people commonly pose or otherwise unnaturally change their expression when a camera is used to take a photograph. In this sense, an image capture device may be able to capture images which more accurately reflect true user experiences, such as laughter during conversation or a genuine but fleeting smile, while traditional cameras are more limited to the images in which the subjects adopt a common pose or “say cheese”.
However, a primary challenge faced by the design and use of image capture devices is the resource-limited environment in which they operate. In particular, the design and use of image capture devices is typically subject to the following constraints: a limited amount of memory to be used for image storage over a significant period of time; a limited amount of processing power or capability to continuously process imagery; a limited amount of energy available to operate over an extended period of time; and/or a limited amount of thermal power that can be dissipated (i.e., a device temperature that should not be exceeded so as to prevent overheating of the device or discomfort for the user, who may in some instances wear the mobile image capture device).
Moreover, performing analysis of audiovisual content captured by an image capture device, such as analyzing a continuous image stream, can be resource intensive. For example, despite advances in the size and ability of image processing chips, image capture devices will still typically have a limited amount of computational power which can be employed at any given moment in time, and further, limited battery resources to power the analysis process. Additionally, the compression, storage, and transmission of audiovisual content, such as images and any associated audio, may be the portions of a typical processing cycle which consume the most significant amounts of power. For example, storing and transmitting full-length video files can quickly deplete an image capture device's battery reserves. Thus, the ability to identify image capture opportunities, intelligently select candidate images for analysis, and generate shortened, edited video files for less resource-intensive transmission in an efficient manner is desirable.